Xiangjing Lai, Jin-Kao Hao*, Zhang-Hua Fu, Dong Yue. Diversity-preserving quantum particle swarm optimization for the multidimensional knapsack problem. Expert Systems with Applications, 2020 https://doi.org/10.1016/j.eswa.2020.113310

The code of the DQPSO* algorithm is available here
The benchmark instances used in the paper are available from http://people.brunel.ac.uk/~mastjjb/jeb/orlib/mknapinfo.html and here

1) Please make sure that the above paper is cited if you use the code in your research.
2) The software is distributed for academic purposes only. If you wish to use this software for commercial applications, please contact the authors.